Poly alkali treatment

S. V. Prasad, C. Pavithran, and P. K. Rohatgi, Alkali treatment of coir fibres for coir-poly-ester composites, /. Mater. Sd. 18(5),1443-1454 (1983). 

Fig. 1A,B. Sephadex G-lOO column chromatography of oligo- and poly(ADP-ribos)ylated Ca, Mg -dependent endonuclease. A H]oligo(ADP-ribos)ylated enzyme, B its chased product with cold NAD. Acid-insoluble radioactivity (A—A), endonuclease activity before ( — ) and after (o—o) alkali treatment, alkali-stimulated endonuclease ( —A). (Data from [5])...

Fig. 1. (left) A release of monomeric ADP-ribose from free and poly(ADP-ribose) S3mthetase-bound poly(ADP-ribose) by the action of poly(ADP-ribose) ycohydrolase. Free poly(ADP-ribose) was prepared from synthetase-bound poly(ADP-ribose) with alkali treatment (Reprinted with permission from ref. 8). 

Poly(ADP-ribose) was purified almost to homogeneity fi om bull testes by the method of Agemori et al. (5). Purified polymerase was incubated briefly with [ P]NAD (10°C, 30 sec, 5 xM NAD) in the presence of 10 pg/ml Hae IH-digested calf thymus DNA. Incorporation was stopped by the addition of 3-aminobenzamide and unincorporated labeled NAD was removed. Pulse-labeled polymer was originally attached to the enzyme. After alkali treatment it showed a heterogeneous distribution of short chains on a 20% polyacrylamide gel (6). Venom phosphodiesterase digested these to p2p]pR AMP and [ P]AMP, of which AMP represented 4.6% of the counts. After a chase with unlabelled NAD (200 pM NAD, 10 min, 25 °C),... 

The poly(e-caprolactone) (PCL) and poly((R)-3-bydroxybutyrate) (R-PHB) films with a hydrophilic surface were prepared by the alkali treatment of their as-cast films in NaOH solutions of different concentrations [154]. The alkali-treated PCL and R-PHB films, as well as the as-cast PCL and R-PHB films, were biodegraded in soil controlled at 25°C. The alkali treatment enhanced the hydrophilicities and biodegradabilities of the PCL and R-PHB films in the soil. The biodegradabilities of the as-cast aliphatic polyester films in controlled soil decreased in the following order PCL > R-PHB > PLLA, in agreement with that in controlled static seawater. 

Tsuji H., Suzuyoshi K., Tezuka Y, Ishida T. Environmental degradation of biodegradable polyesters 3. Effects of alkali treatment on biodegradation of poly(e-caprolactone) and poly((R) -3-hydroxybutyrate) films in controlled soil, J. Polym. Environ. 11 (2003) 57. 

The hydrophilicity of the polymer is increased by introducing theses carboxyl and hydroxyl groups, which can theoretically lead to better cell adhesion during seeding. Such as, Nam et al. [42] reported that the surface modification of PLGA and poly (D,Z,-lactic acid) in the NaOH solution could moderate the surface of the polymers and promote the adhesion of hepatocytes. Gao et al. [44] stated that the surface hydrolysis of PGA meshes in the NaOH solution could increase the attachment ability of vascular smooth muscle cells. However, strong alkali treatment is accompanied with extended bulk degradation of the polyester, and... 

Shen F, Zhang E, Wei Z. In vitro blood compatibility of poly (hydroxybntyrate-co-hydroxyhexanoate) and the influence of snrface modification by alkali treatment. Mater Sci Eng C 2010 30 369-375. 

Y.W., Hamada, H., Semba, T., and Kitagawa, K. (2007) Effects of fiber content and alkali treatment on the mechanical and morphological properties of poly(lactic acid)/poly(caprolactone) blend jute fiber-filled biodegradable composites. J. Biobased Mater. Bioenergy, 1, 78-86. 

Figure 11 IR spectrum of strong polyethylene-poly amine ion exchanger AV-16G after an alkali treatment (1). The spectra of fresh OH (2) and CF (3) forms are presented for comparison. Reprinted from Reactive and Functional Polymers[ i6 with permission from Elsevier ...

CNs have also been incorporated into poly(ethylene-co-vinyl acetate) (EVA) to make EVA/CN composite membranes. Elanthikkal et al. [59] investigated the effect of CN on barrier properties of EVA membranes. Cellulose from banana waste was exposed to alkali treatment, bleaching, and acid hydrolysis to obtain CNs. The resulting CNs were approximately 300 nm long with an average fiber diameter of 30 nm. Tetrahydrofuran was used as solvent to dissolve EVA and to disperse aqueous suspension of CNs. Membranes were obtained by casting-evaporation method. Cellulose fibers were exposed to alkali treatment and bleaching followed by acid hydrolysis. An aqueous suspension obtained after dialysis and ultrasonication was... 

The alkali-catalysed methanolysis of poly(2,2-bis(4-hydroxyphenyljpropane carbonate) (PC) in a mixture of methanol (MeOH) and toluene or dioxane was studied. The treatment of PC in meOH, with a catalytic amount of sodium hydroxide, yielded only 7% bisphenol A. Using a mixed solvent of MeOH and toluene completely depolymerised PC to give 96% free bisphenol A in solid form and dimethyl carbonate in solution. The eharaeteristies of the catalysis are discussed together with the pseudo-first rate kinetics of the depolymerisation. The reaetion eonditions were investigated to facilitate the reeyeling of PC plasties. 17 refs. 

Traces of an optically active anhydroribitol and its phosphates are produced when some teichoic acids are hydrolyzed with alkali.66 67 No anhydroribitol is formed by similar treatment of ribitol, its 1-, 2-, or 3-phosphates, or ribitol 1,5-diphosphate.68 However, small proportions of anhydroribitol and its phosphates are produced by the action of alkali on a synthetic poly (ribitol phosphate) prepared by the action of diphenyl phosphoro-chloridate oil 3,4-O-isopropylideneribitol l-phosphate and 2-phosphate.68 This observation suggests that 1,4-anhydroribitol (13) or its derivatives (15) are produced by fission of a phosphodiester, for example (14), in the manner indicated in Fig. 3, and that this reaction occurs together... 

The proportion of 1,4-anhydroribitol formed by treatment of teichoic acids and synthetic poly(ribitol phosphate) with alkali is small, and the major hydrolytic pathway involves the cyclic phosphate sequence. No 1,4-anhydroribitol glycosides have been observed in the alkaline hydrolyzates of teichoic acids possibly, the presence of a glycosyl substituent makes the reaction sterically less favorable than when such substituents are absent. 

Production of chlorine and sodium hydroxide by electrolysis of aqueous sodium chloride is the basis of the chlor-alkali industry, a business that generates annual sales of approximately 4 billion in the United States alone. Both chlorine and sodium hydroxide rank among the top 10 chemicals in terms of production Annual output of each in the United States is 11-12 million tons. Chlorine is used in water and sewage treatment and in the manufacture of plastics such as poly(vinyl chloride) (PVC). Sodium hydroxide is employed in making paper, textiles, soaps, and detergents. 

Treatment of the 5 -phosphate of cytidine or adenosine with methyl sulfate at pH 5 yields iV -methylcytidine 5 -phosphate and iV -methyl-adenosine 5 -phosphate (244), along with their (methyl phosphate) derivatives. When the methylated adenylic acid (244) is treated with a mild alkali, a Dimroth rearrangement occurs, with formation of A -methyladenosine 5 -phosphate (245). Methylation of the synthetic homopolymer poly (adenylic acid) with methyl sulfate, followed by adjustment of the pH of the reaction mixture to pH 11, gave a polymer that contained an appreciable percentage of iV -methyladenylic acid residues in the polynucleotide chain. 

Niobium (formerly known as columbium) and tantalum occur together in the mineral columbite (Fe,Mn)(Nb,Ta)20g when Nb-rich, it is called niobite and when Ta-rich, tantalite. Fusion of the ore with alkali gives poly-niobates and -tanta-lates, and further treatment with dilute acid yields Nb205 and Ta205. One method of separation utilizes the more basic character of Ta at a controlled concentration of HF and KF in aqueous solution, the oxides are converted to... 

Alkali and acid treatments have also been used to modify surface properties of polymers sulfonated polyethylene films treated first with ethylenediamine and then with a terpolymer of vinyhdene chloride, acrylonitrile, and acrylic acid exhibited better clarity and scuff resistance and reduced permeabihty. Permanently amber-colored polyethylene containers suitable for storing light-sensitive compoimds have been produced by treating fluorosulfonated polyethylene with alkali. Poly(ethylene terephthalate) dipped into trichloroacetic/chromic acid mixture has improved adhesion to polyethylene and nylons. Antifogging lenses have been prepared by exposing polystyrene films to sulfonating conditions. Acid and alkali surface treatments have also been used to produce desired properties in polymethylmethacrylates, polyacrylonitrile, styrene-butadiene resins, polyisobutylene, and natural rubber. Surface halogenation of the diene polymers natural rubber and polyisobutylene resulted in increased adhesion to polar surfaces. 

CigHioO, Mr 338.27, brown plates or powder, mp. 320 °C (decomp.). Component of the fruit bodies of Boletopsis leucomelaena (=Polyporus leucomelas, Basidiomycetes). C. is identical to leucomelone for which the erroneous structure of a 2-(3,4-dihydroxy-phenyl)-3,5-dihydroxy-6-(4-hydroxyphenyl)-p-ben-zoquinone was previously assumed. In B. leucomelaena and the fruit bodies of various Anthracophyllum species C. occurs in free form or in the form of leuco compounds that are partially or completely acetylated. These compounds are responsible for the green color reaction of fruit bodies on treatment with alkalis. Poly-acetylated leucocycloleucomelones are effective inhibitors of 5-lipoxygenase. 

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